An update to the Battle.net Forums has the latest on the seemingly endless saga of the upcoming version 1.13 patch for Diablo II (thanks Rhialto). Blizzard's desire to update their action/RPG which is now over nine years old is laudable, so it seems forgivable that this patch has been in the works since at least March, about 8% of the game's lifespan (though the record for this is probably the 14-month development of Battlefield 2 1.50, which was over a quarter of the game's lifespan at that point). Word is the expanded stash that was holding things up has been dropped, but that the patch is still a ways off:

We've recently completed a revised version of the Diablo II 1.13 patch that removes the increased stash size. A larger stash will unfortunately no longer be a feature included in patch 1.13 due to the previously mentioned concerns. As higher priority work continues on Warcraft III we're hoping to complete our quality assurance tests for the 1.13 patch in the next few weeks. But as always, the types of issues that may appear and take higher priority are rarely foreseeable. We continue to plan a release based on our best intentions.